Tornadoes are at their most devastating in the US when late spring and early summer weather systems create perfect conditions for massive storms, the Met Office said today.
Forecaster Helen Chivers explained that tornadoes form when air temperatures with varying moisture levels travel huge distances across the continent to clash in the Mid West.
“You get cold or cool, dry air blowing down from the Rocky Mountains or the Northern Plains. Then there’s an injection of hotter, dry air coming from the deserts, possibly from Nevada. These two collide with warm, humid air that’s blowing north from the Gulf of Mexico.
“When these meet you get massive thunderstorms forming, which create spinning columns of air — tornadoes.
“The key factor is cool, dry air hitting warm moist air. At this time of year the concentrations of these different conditions are at their most marked.
“Late spring and early summer are the most perfect times of year for a tornado to form. They create a front in Tornado Alley that stretches from Nebraska to Texas.”
